Fans were able to take batting practice, run the bases and throw in the bullpen, but the highlight for most were autograph sessions with the players and question-and-answer sessions with players, broadcasters and members of the front office.
The players, especially those new to the organization, seemed to enjoy FanFast as much as the fans.
"It's been great," said Feldman, who signed a three-year, $30 million contract with the Astros in December. "I signed a lot of autographs and answered some questions, and everybody seems excited for the upcoming season."
Feldman was one of several major acquisitions the Astros made this offseason, joining outfielder Dexter Fowler and relievers Matt Albers, Chad Qualls and Jesse Crain. Fowler didn't attend FanFest because he's newly a father, but Albers, Qualls and Crain enjoyed catching up with fans and their new teammates.
"It's been good," said Crain, who played at the University of Houston and lives in the area. "It's nice to see my teammates and put a face to the names and, of course, to come out and see the fans and represent the Astros. It's been my hometown, and it's fun to wear this jersey and be a part of this team.
"Usually, when you live somewhere [not in your hometown], you're going somewhere else to meet the fans, but to do it in your own community, it's fun. It's important to come out here and show your support for the fans because it means a lot."
Albers and Qualls, of course, are no strangers to Astros fans.
Both were drafted and developed by the Astros and made their Major League debuts at a time when Houston was considered a baseball town. They were both traded within a couple of days of each other in 2007 and reconnected Saturday with fans who still remembered them well.
"They were saying, 'It's good to have you back. I remember '04, '05,'" said Qualls, who pitched in the World Series for the Astros in 2005. "That was kind of when the city was going crazy and we were winning a lot of games. It was awesome, and the stadium was packed and full of people.
"The past couple of years I'd come here as a visitor and not see many people in the stands, so we've got to get the winning back here and get more people here. If I can be a part of that and bring Houston back to where we were, that would be awesome."
Albers said returning to Minute Maid Park in an Astros uniform meant he's come full circle.
"I got called up in 2006 and made my Major League debut in the same game Roger Clemens started, and that was pretty awesome," he said. "The place was packed with 40,000 fans. Hopefully, that's where we're headed, to play well enough to get all the fans back in here. All the fans here at FanFest have been really great and are excited to have me back. Hopefully, I can keep up my end of the bargain and pitch well."
FanFest capped a weeklong series of appearances by Astros players and staff during the Astros Caravan, in which the Astros traveled from San Antonio to Oklahoma City to Baton Rouge, La., and dozens of points in between. The fans are excited about the newcomers, as well as returning stars like Jose Altuve and Jason Castro, who were hits Saturday.
Astros prospects Carlos Correa and Mark Appel -- the No. 1 overall picks in the last two First-Year Player Drafts -- and George Springer also signed autographs at FanFest for eager fans excited what the future might hold in Houston.
"I think this whole week, the support from the fans has been incredible," general manager Jeff Luhnow said. "Everywhere I've been -- San Antonio, Austin and Houston -- they've been coming out. The expectations are getting higher, and the evidence of what we've been doing in the Minor League level is starting to manifest itself. We are building this thing the right away, and it's going to start showing up at Minute Maid Park in a very positive way in 2014, and I think our fans are excited about that."